Device for eliminating oxidation during hot stretching operation on grids



June 3, 1958 F, J. HUGHES ET AL 2,83

DEVICE FOR ELIMINATING OXIDATION DURING HOT STRETCHING OPERATION ON GRIDS 2 Sheets-Sheet 1 Filed Nov. 20, 1953 June 3, 1958 F. J. HUGHES ET AL 2,837,

DEVICE FOR ELIMINATING OXIDATION DURING HOT STRETCHING OPERATION ON GRIDS Filed Nov. 20, 1953 Z'Sheets-Sheet 2 70 K K 3 K 2) NITROGHV W SUPPLY ATTOR Y Unite DEVICE FOR ELIMINATING OXIDATION DURING. HOT STRETCHING OPERATION ON GRIDS Frank J. Hughes, Levittown, and Robert McGhee, Massapequa Park, N. Y., assignors to Sylvania Electric Products Inc., a corporation of Massachusetts The invention relates to electrode manufacture under an inert or reducing atmosphere.

More particularly the invention relates to hot stretching of grids while they are on a grid winding machine, this stretching taking place while the grids are in a chamber supplied with an inert or a reducing gas.

In the operation of winding the grid laterals around the grid side rods, the necessary notching and peening of the side rods to lay the grid laterals therein results in distortion of the grid string. In the prior art, after a string of grids had been formed, and as exemplified in the patent to Herzog 2,272,869, issued February 10, 1942,

it had been proposed to pass a current through the grids and while hot effect a stretching of the grid support rods to straighten the same. In doing so, however, the grids become oxidized and possibly scaly requiring furthercleaning treatment. This required separate handling of Patent the grids, involving fraying of the grids and subjecting the same to cleaning and drying steps. It is an object of this invention to obviate this handling and replace the same by a simple time and labor saving operation which is performed on the grid winding machine itself.

For a clear understanding of our invention, attention is directed to the following specification and claims taken in conjunction with the accompanying drawings in which:

Fig. 1 is a perspective view of our attachment including a reducing chamber and its mounting means as applied to a portion of a grid winding machine.

Fig. 2 is a diagrammatic View of the attachment showing the relationship of the reducing chamber with control and supply devices.

Fig. 3 is a side elevation of the structure in Fig. 1 with the reducing chamber and adjacent parts shown in section and a support arm also shown in section.

Fig. 4 is a sectional view through the reducing chamber with a series of grids therein, and

Fig. 5 is a diagrammatic view showing the relationship between the reducing chamber and parts of the grid winding machine.

Referring to the drawings more in detail, there is disclosed an angular, roughly Z-shaped, bracket 10 comprised of a horizontal arm 12, a vertical leg 14, and a lower ofiset arm 16 parallel to the arm 12. The arm 12 is fastened to a stationary support 18 on the grid winding machine, as by screws 20.

The arm 16 has thereon an upstanding block 22 preferably integral therewith. This block is a parallelepiped with a pintle 24 extending through the upper portion of the block, the pintle being parallel to the lower arm 16. The pintle provides a pivot for a platform 26 having depending ears 28 pivoted on the pintle.

Fastened in any desired manner to the forward end of the platform is a supporting plate 30 to which is secured by welding or otherwise a slotted tubular cylinder 32,

' see Fig. 3, the interior of which forms a chamber to ice shown in Figs. 3 and 4. A pair of circular end plates 36 with slots 38 therein, in the vertical plane of the slot 34, substantially close off the ends of the cylinder. To prevent leakage of gas through the slot 34, a sleeve 40, slotted longitudinally as shown at 42, snugly and rotatably surrounds the cylinder 32. To permit guided rotation of the sleeve on the cylinder, the sleeve 40 is provided with a cut out portion 44. This cut out portion comprises an arc of a length to permit the slot 42 to move from the position shown in Figs. 1 and 3 to a position such that the slots 34 and 42 are in register. When these slots are in register, the platform 26 may be tilted about the pintle 24 to raise the cylinder and sleeve out of the way of a grid strip 46 within the cylinder. For convenience in rotating the sleeve 40 and for raising and lowering the chamber a handle, not shown, may be suitably secured to the sleeve. To further assist in raising and lowering the chamber and to gravitationally maintain the same in either raised or lowered position the sleeve and cylinder are counterbalanced by a weight 50 secured in any convenient manner to an upright 52 welded or otherwise fixed to the platform 26, the center of mass of the weight being to the rear of the pintle or pivot 24. Due to the right angular relationship of the lever arm carrying the chamber and the counterweight, the chamber will be held, by gravity, in either its up or down position. In order to variably limit the pivotal movement of the platform 26, the same is provided with two adjustable stop screws, 54 and 56, the stop screw 54 being forward of the pintle 24 and engageable with the top surface of block 22, while the stop screw 56 is backward of the pintle and engageable with the back face of block 22.

Within the cylinder is a horizontal header pipe 58 having a row of perforations 60 therein, preferably at the top thereof. This pipe extends longitudinally of the chamber and extends to within a short distance of the ends thereof. To supply this pipe with an inert or reducing gas, such as nitrogen, helium or hydrogen, or a forming gas (a mixture of nitrogen and hydrogen) there is provided an induction pipe 62 leading to the gas supply. When the chamber is in lowered position surrounding the grid string, gas is permitted to flow into the chamber at a slow rate. Any gas escaping from the ends of the chamber is dissipated into the atmosphere without harm, particularly, if the gas be an inert gas. But if desired, a suction hood, not shown, may encompass the ends of the chamber to withdraw from the vicinity of the machine any gas escaping from the chamber. When the chamber is raised, the gas flow is automatically cut off by means soon to be described.

Mounted on the platform 26 is a right angled bracket 64 provided with resilient clips 66 supporting a mercury switch 68. This switch controls a gas valve 7t). Where the gas is a forming gas the valve 70 permits compressed nitrogen stored in tank 72 to flow through a two stage pressure reducing valve 74 and thence through a flow meter 76 to a bubbling tank 78 containing methanol or isopropyl alcohol. To assist in forming a proper mixture, glass beads may be placed at the bottom of tank 78. The gas mixture is then fed via pipe 62 to the header 58.

When the chamber is lowered the mercury switch 68 operates to close the circuit and the valve is turned on; when raised, the mercury switch opens the circuit and the valve is turned off. Thus no gas flows to the chamber when the chamber is in raised position; and the gas flow, when it does flow, is at a very slow rate.

The chamber is lowered to surround the grid string after a length of grids have been wound and after the winding machine has been stopped. Concurrently with the lowering of the chamber, the gas flow thereto is established.

3 Then the heating circuit to the grids is closed and the grid string stretched.

In Fig. 5 there is illustrated, diagrammatically, the association of the chamber with other parts of the grid winding machine, the portion 80 representing the means for rotating the grid side rods and the means for applying the grid laterals to the side rods and the portion.

82 representing the grid string feeding and stretching device,v the arrows indicating the direction of movement of said device. The circuit for heating the grid string is indicated at 84, it being understood of course that one leg of the circuit is insulated from ground as by an insulating section 86.

Having thus described our invention What we claim as new is:

1. A device for hot stretching a string of grids while in a non-oxidizing atmosphere comprising a chamber mounted for movement to and from a position encompassing the string of grids, valve means under control of a part movable with said. chamber for supplying said chamber with a non-oxidizing medium when the chamber encompasses the string, means for heating the grid string while within said chamber, and means for simultaneously stretching said grid string while in said chamber.

2. A device for use in hot stretching grids comprising a hollow cylinder forming a chamber therein, said cylinder being slotted at the bottom and movable to and from a position encompassing the grids, means supporting the cylinder for such movement, means for supplying said chamber with a gas and means responsive to the position of the cylinder for. controlling the flow of gas to said chamber.

3. A device for use in hot stretching grids comprising a hollow cylinder having a. slot at the bottom thereof 'and having slots in the end Walls with the slots in the plane of the slot at the bottom of the cylinder thereby forming.

a substantially closed chamber, said cylinder being movable to and from a position encompassing the grids, means supporting the cylinder for such movement, means for supplying said chamber with a gas and means responsive to the position of the cylinder for controlling the flow of gas to said chamber.

4. A device for use in hot stretching grids comprising a hollow cylinder having a slot at the bottom thereof and having slots in the. end walls with the slots in the plane of the slot at the bottom of the cylinder thereby forming a substantially closed chamber, a sleeve having a slot registering with the slot at the bottom of the cylinder, said sleeve being rotatably mounted on the cylinder to bring its slot out of register with the bottom slot of the cylinder, said cylinder and sleeve being movable to and from a position wherein the cylinder encompasses the grids, means supporting said cylinder and sleeve for such movement, means for supplying said chamber with a gas and means responsive to the position of the cylinder for controlling the flow of gas to said chamber.

5. A device for use in hot stretching of grids comprising a pivoted counter-balanced hollow cylinder slotted at the bottom thereof, means for supplying the interior of said cylinder with a gas and means responsive to the pivotal movement of said cylinder to control the flow of said gas.

6. A device for use in hot stretching of grids comprising a support bracket, a bell crank lever pivoted on said support at a point on said lever close to the knee of the lever, a horizontal hollow cylinder split at the bottom carried at one end of the lever, a counterweight carried by the other end of the lever, means for limiting the pivotal movement of the lever, and means for supplying said hollow cylinder with a gas.

References Cited in the tile of this patent UNITED STATES PATENTS Great Britain Apr. 13, 

